I have added a "debugger;" in the top of the javascript(please see below code sample), then click "+" on top of view to launch create form, at the same time press "F12" to show the IE devTools.
var test = false; // global variable
debugger;
onload = function () {
}
onchange = function () {
}
The process will stop at the line of "debugger;" twice.
Looks like a dynamics bug?